Tehran University Medical Journal

Background: Auditory brainstem response (A.B.R) is one of the most important electrophysiological tests in evaluating of auditory system, especially for diagnosing of auditory nerve and brainstem disorders. It is a non-invasive test and has reliability and validity characteristic. There is no contra-indication for this test. One of the most important of stimulation parameters of A.B.R is click polarity (rarefaction, condensation and alternative). Some of the investigators believed that different polarities have no effects on A.B.R are affected by different polarities.

Materials and Methods: In this study, the results of ABR of 148 patients (296 ears) were compared with three different polarities of rarefaction, condensation and alternative half click stimuli. The cases were categorized in three groups of normal (60 cases), cochlear (62 cases) and retro-cochlear (17 cases). This classification were done according to the hearing level in pure tone audiometry results in three frequencies of 1000, 2000, 4000 Hz and to the site of the their disorders. The mean absolute latencies of waves I, III and V were obtained for each polarity. Inter-peak latency (I.P.L) of wave also measured in three groups (normal, cochlear and retro-cochlear).

Results: The results were showed a significant difference between absolute latency of wave I among different polarities on three above mentioned groups (P<0.05). There were no significant discrepancy for other waves of III and V and Inter-peak latency (I.P.L) of wave I to (P>0.05).

Conclusion: It was concluded that rarefaction polarity has better and more stable results of ABR tests.

Background and Aim: Auditory and visual stimuli are the most important factors in communication. It seems during the brain maturation, decrease of visual inputs causes enhancement of somatosensory and auditory cortical responses. In this research latency and amplitude of auditory middle latency responses (AMLR) are studied in blinds and normally sighted subjects.

Materials and Methods: This descriptive-analytical study was performed on 40 congenitally blinds and 40 normally sighted subjects in the range of 14-20 years. All of cases had normal hearing sensitivity and acoustic reflexes without any middle ear disorders. The reason of this age range is the maturation of auditory middle latency responses. Sampling was randomized.

Results: There was significant difference between amplitude of Na, Pa & Nb waves and latency of Na while no significant difference between latency of Pa & Nb in blinds and normally sighted subjects.

Conclusion: Increase of amplitude and decrease of latency of AMLR in blind subjects were due to sensory compensation phenomenon, probably. It seems rate of processing and auditory perception in blinds is better than normally sighted subjects.

Background: Preterm labor is a major contributor to neonatal morbidity and mortality and results in increased obstetric and pediatric care costs. The purpose of this study was to assess the effects of vaginal progesterone for maintenance therapy following treatment of threatened preterm labor for preventing preterm birth.
Methods: The study included 70 singleton pregnant women with preterm labor with intact membranes. Patients were randomized to receive either maintenance vaginal progesterone therapy (n=37) administered (400 mg) daily or no treatment (controls, n=33) after discontinuation of acute intravenous tocolysis.
Results: The two groups were similar with at respect to maternal age, race, parity, gestational age at admission, bishop score, and preterm delivery risk factors .Compared to the control group, the mean ±SD time gained from initiation of maintenance therapy to delivery (36/1117/9 versus 24/5227/2) (meanSD) days, p=0.037) and the gestational age at delivery (36.071.56 vs. 34.51.3 weeks, p=0.041) were higher in the vaginal progesterone maintenance therapy group. No significant differences were found with recurrent preterm labor 13 (35.1%) versus 19 (57.6%), p=0.092. Respiratory distress syndrome 4 (10.8%) versus 12 (36.4%) p=0.021, Low birth weight10 (27%) versus, 17 (51.5%) p=0.04, birth weight (3101.54±587.9gr versus r 2609.39±662.9gr, p=0.002) were significantly different between the two groups.
Conclusion: The gestational age and time gained from initiation of maintenance therapy to delivery were longer in women receiving vaginal maintenance tocolysis with progesterone and improve perinatal outcomes. However, maintenance therapy did not decrease the recurrence of preterm labor episodes.